Android EditText limit input to range of numbers

Question

I am trying to limit a numeric edittext only to a range of numbers. I have found some tutorials that use InputFilter to do this but once implemeted I cannot type into the EditText anymore.

As per tutorials I create a class as:

package africa.mykagovehicles;

import android.text.InputFilter;
import android.text.Spanned;

public class InputFilterMinMax implements InputFilter {
    private int minimumValue;
    private int maximumValue;

    public InputFilterMinMax(int minimumValue, int maximumValue) {
        this.minimumValue = minimumValue;
        this.maximumValue = maximumValue;
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        try {
            int input = Integer.parseInt(dest.subSequence(0, dstart).toString() + source + dest.subSequence(dend, dest.length()));
            if (isInRange(minimumValue, maximumValue, input))
                return null;
        }
        catch (NumberFormatException nfe) {
        }
        return "";
    }

    private boolean isInRange(int a, int b, int c) {
        return b > a ? c >= a && c <= b : c >= b && c <= a;
    }
}

Then in the activity I set the InputFilter with:

txtYearOfManufacture.setFilters(new InputFilter[] {new InputFilterMinMax(1950, 2020)});

No clue why I can't type into the EditText. Any help appreciated.

Answer 1

Try to change the code as follows

import android.text.InputFilter;
import android.text.Spanned;


public class InputFilterMinMax implements InputFilter {
    private int minimumValue;
    private int maximumValue;

    public InputFilterMinMax(int minimumValue, int maximumValue) {
        this.minimumValue = minimumValue;
        this.maximumValue = maximumValue;
    }
    public InputFilterMinMax(String minimumValue,String maximumValue) {
        this.minimumValue = Integer.parseInt(minimumValue);
        this.maximumValue = Integer.parseInt(maximumValue);
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        try {
            int input = Integer.parseInt(dest.subSequence(0, dstart).toString() + source + dest.subSequence(dend, dest.length()));
            if (isInRange(minimumValue, maximumValue, input))
                return null;
        }
        catch (NumberFormatException nfe) {
        }
        return "";
    }

    private boolean isInRange(int a, int b, int c) {
        return b > a ? c >= a && c <= b : c >= b && c <= a;
    }
}